Recently, in an automobile industry, technique for joining different kinds of materials such as aluminum and iron members which are hardly weldable together has become more and more important since lightweight material such as an aluminum member has been positively utilized from a viewpoint of making a vehicle light in weight for improvement of fuel efficiency. Conventionally, different kinds of materials hardly weldable together have been joined together by means of, for example, bolt-on fastening, joining through mechanical clinch or adhesion through adhesive agent.
Conventional technology pertinent to a method for joining materials of the invention has been disclosed, for example, in the following Reference 1.
[Reference 1] JP 2004-136365 A